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Edexcel Physics Unit 4 - 21st June 2011

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Reply 580
Original post by inspiringsoul
2nd last ques ws weird, n didnt get 'confirm mass of sulper ion is 0.00001u ??!!!!
frm where do they get such ques? lol.


i think u have to use 3pp 10 million on a mass of on sulphur... that would give something like 0.000009u.... so it rounds up to 0.00001u (what they asked)... LC. is hence 0.0001u
Reply 581
Can any one who actually got the second and third parts for the spreadsheet question please quote me ..... it was to find the speed and displacement... i tried using a centripetal force... and equate a to v2/r but it didnt work.........still wrote the workings though...
Reply 582
I admit, it wasn't an especially tough piece of paper, in terms of what you need to know. I revised back to front and in and out for this paper, until i am about 98% ready, but I didn't use the lot of my knowledge while doing it. Heck, most of the theories are in the OBJECTIVES. It's more of an application's type paper. Unpredictable. And it sucks. I lost marks on spreadsheet and the 4 mark question about the pendulum ball between plates for proving electric field.. WHAT IS THAT?! How does it even connect?
Reply 583
Original post by VickyThomas
I wrote that the field caused it to be held in place as it was repelling from both positive sides, and attracting equally from both negative sides so that held it in place. Did you say that force was going towards the centre of its orbit in the first part of the question, saying that was its centripetal force keeping it in circular motion? Fleming's LHR and all...


I should have written Fleming's left hand rule. In that small space, I wrote it was perpendicular to force and current so it enclosed in a circular motion. but all that description does not fit in. LOL

Original post by Bleo
I should have written Fleming's left hand rule. In that small space, I wrote it was perpendicular to force and current so it enclosed in a circular motion. but all that description does not fit in. LOL


It was only two marks anyway so you probably got them both from that. I crossed out Fleming's LHR and just described what you wrote in the end.
One messed up paper. =.=
Yeah for circular motion it was obviously the force was perpendicular to direction of motion. hence it undergoes circular motion
ok can any1 remember their mcqs answers?
Guys for the last question conservation part did u all answer it somewhat like this
Charge needs to be conserved (showed charge conserved)
Energy, mass and momentum needed to be conserved ... There might be some nucleus or neutron which might have collided in order for momentum to be conserved ... Gamma ray photons might be produced for energy and mass to be conserved..
what was the gradient for u all in the 1st question?? 0.045 or something??
What did you choose as an answer for the coils Y and X in the multiple choice section?
I thought the paper was ok except for that spreadsheet question. Heres what i remember from it:
Mcqs Cant really remember the order :s-smilie:
1. Weight
2. loop contracts into a circle
3. time constant = seconds
4. Open the switch
5. 4*10^-4 Wb
6. Particle is moving closer to the speed of light
7. 10MeV/c^2
8. To collide hadrons
(im sure i missed some question :P)

Structured
Proof was easy i got that and the wavelength was 2.something *10^-11
describing the velocity time graph was easy - you just have to say it accelerates firsts and then accelerates in the opposite direction and why ( due to the resultant force acting on the ball because of the electric force it experiences in the field)
The speed of the bat after collision was 0.56m/s (if you used 0.8) or 0.52m/s (if you used 0.77). Even though the difference in the KEs was small - there was still a difference therefore - inelastic (from the students conclusion)
However - am i the only person who noticed that the final KE > initial KE ???? Thats why they asked the about the uncertainty of the student measurement of the height x - the students value was too big because final ke cannot be greater than initial KE - thats impossible because energy is lost during the collision as heat or sound)
Spreadsheet - i managed to prove the first part - couldnt do D5 but i proved E6 using s=ut+.5at^2
Max radius= 2.9*10^-14
Conclusions of Rutherford expt - i think everyone knew this :P
The jelly question with the graph - it was a straight line and you have to find the negative gradient. The constant was 0.00625cm^-1 (or 6.25m^-1) (of course there would be a range for this answer because it depends on your graph)
Particl physics question was simple - for the conservation i guess you can talk about any 3 of 6 things that are conserved : Charge, Mass/Energy, Baryon Number, Lepton Number,Strangeness and Momentum
For the question with sulphur - the change in mass was 0.00233u or something which was much greater than the least count of the trap (0.00001u) therefore it can be measured
Sorry if i missed out something :smile:
Original post by VickyThomas
What did you choose as an answer for the coils Y and X in the multiple choice section?


I said coil becomes parallel to field.

My thinking was induced current opposes change that produced it.
Original post by i_hate_teeth

Original post by i_hate_teeth
I said coil becomes parallel to field.

My thinking was induced current opposes change that produced it.


oh no I meant the one that said in the multiple choice section 'Coil X and Y are parallel to one another, when the switch is closed Y rotates (I think it said rotates..' and then it asked how you could get X to do the same thing. Options were something like 'No changes made to the arrangement' then 'Reduce the resistance', or 'Move the coils closer together' or there was another one, I can't remember the last option.
Original post by VickyThomas
oh no I meant the one that said in the multiple choice section 'Coil X and Y are parallel to one another, when the switch is closed Y rotates (I think it said rotates..' and then it asked how you could get X to do the same thing. Options were something like 'No changes made to the arrangement' then 'Reduce the resistance', or 'Move the coils closer together' or there was another one, I can't remember the last option.


I don't remember this question.. The only question I remember with two coils was the question about flux linkage.
Original post by VickyThomas

Original post by VickyThomas
oh no I meant the one that said in the multiple choice section 'Coil X and Y are parallel to one another, when the switch is closed Y rotates (I think it said rotates..' and then it asked how you could get X to do the same thing. Options were something like 'No changes made to the arrangement' then 'Reduce the resistance', or 'Move the coils closer together' or there was another one, I can't remember the last option.


The other one was "open the switch" - and its not rotates - the arrow showed the direction of current and it asked how to get the current to flow in the same direction as the first coil
Read above ^ :P
Reply 596
Original post by Studentboii
I thought the paper was ok except for that spreadsheet question. Heres what i remember from it:
Mcqs Cant really remember the order :s-smilie:
1. Weight
2. loop contracts into a circle
3. time constant = seconds
4. Open the switch
5. 4*10^-4 Wb
6. Particle is moving closer to the speed of light
7. 10MeV/c^2
8. To collide hadrons
(im sure i missed some question :P)

Structured
Proof was easy i got that and the wavelength was 2.something *10^-11
describing the velocity time graph was easy - you just have to say it accelerates firsts and then accelerates in the opposite direction and why ( due to the resultant force acting on the ball because of the electric force it experiences in the field)
The speed of the bat after collision was 0.56m/s (if you used 0.8) or 0.52m/s (if you used 0.77). Even though the difference in the KEs was small - there was still a difference therefore - inelastic (from the students conclusion)
However - am i the only person who noticed that the final KE > initial KE ???? Thats why they asked the about the uncertainty of the student measurement of the height x - the students value was too big because final ke cannot be greater than initial KE - thats impossible because energy is lost during the collision as heat or sound)
Spreadsheet - i managed to prove the first part - couldnt do D5 but i proved E6 using s=ut+.5at^2
Max radius= 2.9*10^-14
Conclusions of Rutherford expt - i think everyone knew this :P
The jelly question with the graph - it was a straight line and you have to find the negative gradient. The constant was 0.00625cm^-1 (or 6.25m^-1) (of course there would be a range for this answer because it depends on your graph)
Particl physics question was simple - for the conservation i guess you can talk about any 3 of 6 things that are conserved : Charge, Mass/Energy, Baryon Number, Lepton Number,Strangeness and Momentum
For the question with sulphur - the change in mass was 0.00233u or something which was much greater than the least count of the trap (0.00001u) therefore it can be measured
Sorry if i missed out something :smile:




I also got an increase in K.E.... initial was like 0.94 soemthing (cant remember the zeros) and final was like 0.98.... so i said its in-... wait for it elastic...../.... *pokerface*


Who was that sadonic good for nothing person who neg repped this post because there was a neg rep button?
(edited 12 years ago)

Original post by DHSN
I also got an increase in K.E.... initial was like 0.94 soemthing (cant remember the zeros) and final was like 0.98.... so i said its in-... wait for it elastic...../.... *pokerface*


I think that only works with Legendary :P Lol
Reply 598
Original post by Studentboii

The speed of the bat after collision was 0.56m/s (if you used 0.8) or 0.52m/s (if you used 0.77). Even though the difference in the KEs was small - there was still a difference therefore - inelastic (from the students conclusion)
However - am i the only person who noticed that the final KE > initial KE ???? Thats why they asked the about the uncertainty of the student measurement of the height x - the students value was too big because final ke cannot be greater than initial KE - thats impossible because energy is lost during the collision as heat or sound)


Original post by DHSN
I also got an increase in K.E.... initial was like 0.94 soemthing (cant remember the zeros) and final was like 0.98.... so i said its in-... wait for it elastic...../.... *pokerface*


Thank God someone points out that there was an increase in KE :banana:

I scrolled through the previous pages and no one mentioned that...
(edited 12 years ago)
I thought I was the only one, I thought i made a mistake on that question (lost in ke)

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